This invention relates primarily to town house construction employing three-dimensional modules. It also applies to other types of housing plus educational, community and office facilities.
Government housing experts have stated that this nation's projected demand for twenty-six million housing units over the next ten year period can be achieved, if at all, only through industrialized or factory-produced housing. Many manufacturers who are aware of this have been developing, and some have already built, particular kinds of industrialized housing units, each of which, no matter what the material, can be generally characterized as belonging to one of three basic structural or envelope systems or to combinations of them:
(1) skeletal, with components (structural frame with in-filled non-bearing wall panels);
(2) panel, with components (structural floor and wall panels);
(3) three dimensional or modular, with or without major components (boxes or sections of houses or buildings).
Of these three, modular systems allow the most work to be done in the factory and necessitate the least amount of work in the field, and the present invention relates to a basically modular system. Factory pre-manufacturing and pre-finishing can be most completely realized by the modular system, and to do so has many advantages. For one thing, factory wages are substantially less than field wages. Also, a factory generally offers better working conditions and can accommodate year-round work. Further, factory work can have a one-shop jurisdiction, which can mean more efficient operation, because any one man is able to do more than one task. In addition, assembly line efficiency is greater than on-site work.
Most multi-family modular systems in use today call for the units to be partially or fully pre-finished in the factory, so that interior partitions, doors, fixtures, equipment, windows, etc., are installed in the modules in the factory. However, when the fully pre-finished modules have heretofore been assembled into a building, assembly has resulted in non-functional redundancy of materials, i.e., double walls or double floors within the same living unit where it has not been functionally needed. Cost estimates indicate that this redundancy typically adds to the cost 80.cent. to $1.60 per square foot of floor area, depending upon the system and the area. Moreover, most of such systems have been based upon a mobile home sectionalized unit,--a very inflexible system for different unit distributions and packing possibilities.
On the other hand, where heretofore attempts have been made to eliminate redundancy, wherein modules are stacked in an alternated or checkerboard pattern, developing so-called "free spaces", it has been very difficult to finish the free spaces at the factory, and as a result, the cost of on-site finishing has been increased by approximately $1.00 to $2.00 per square foot. Furthermore, such systems when applied to townhouses either over design their interior unit walls or must add material to their unit party walls in order to achieve satisfactory noise and fire retardation performance specifications. Also, the economic need to have bathroom and kitchens in modules rather than as "free" spaces, so that they could be preassembled, has been a restraint on the flexibility of these non-redundant systems heretofore available.